Highways and railroads become obsolete, airplanes no longer need wings, and oceangoing ships can be broken up for scrap. Industries in which large masses have to be transported or supported - from mining to construction - are revolutionized. Citizens gain unprecedented mobility, transcending all geographical and national barriers.

Meanwhile, space travel is now safe, cheap, and fast. Resources can be mined in the asteroid belt and shipped to factories relocated in orbit around Earth, freeing our planet from pollution and greenhouse-gas emissions. Ultimately the old dream of colonizing other worlds may be realized, not just for a handful of highly trained astronauts but for millions of everyday people.

Highways and railroads become obsolete, airplanes no longer need wings, and oceangoing ships can be broken up for scrap. Industries in which large masses have to be transported or supported - from mining to construction - are revolutionized. Citizens gain unprecedented mobility, transcending all geographical and national barriers.

Meanwhile, space travel is now safe, cheap, and fast. Resources can be mined in the asteroid belt and shipped to factories relocated in orbit around Earth, freeing our planet from pollution and greenhouse-gas emissions. Ultimately the old dream of colonizing other worlds may be realized, not just for a handful of highly trained astronauts but for millions of everyday people.

OK, I'm imagining a fairy tale world.So what?It's not the world I live in.